# Sinus Tumors in Cats: Signs, Diagnosis, and Treatment Options A sinus tumor in cats is an uncommon cancer that grows inside the nose or the air-filled sinuses behind it. Most cats with this problem first show up at the vet for something that looks like a stubborn nasal infection, a bloody nose, or noisy breathing that will not clear up. The average cat is diagnosed around 12 years of age, and more than 90% of these tumors are malignant [1]. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - The most common sign is long-lasting nasal discharge that may contain mucus, pus, or blood, and it often starts on one side before becoming two-sided [1]. - More than 90% of nasal tumors in cats are cancerous, and the most common types are carcinomas and lymphomas [1]. - Untreated, survival is generally 3 to 5 months after diagnosis [1]. - A CT scan is the preferred imaging test and is more reliable than rhinoscopy for detecting a nasal tumor when only one procedure can be done [1][2]. - A biopsy is what gives a definite diagnosis, and the tumor type guides which treatment makes sense [1]. ## What Is a Sinus Tumor in Cats? The nose and sinuses are lined with tissue that can develop abnormal growths. When those growths are tumors, they can block airflow, press on bone, and cause discharge or bleeding. In cats, tumors of the nose and sinuses are relatively uncommon compared with dogs, and the incidence is higher in male cats [1]. Most of these growths are malignant, meaning they can invade nearby tissue and sometimes spread. The two most common types are carcinomas and lymphomas [1]. Carcinomas are the second most common intranasal tumor in cats [3]. Nasal lymphoma is the most common nasal tumor overall and tends to be a solitary, radiosensitive tumor [4][5]. Because the signs overlap so heavily with ordinary nasal disease, owners often spend weeks or months treating what seems like a chronic cold or allergy before a tumor is suspected. ## Signs Owners Notice First ### Nasal discharge that will not quit Chronic nasal discharge containing mucus, pus, or blood is the most common sign [1]. At first the discharge may come from just one nostril, but it often becomes two-sided as the tumor grows [1]. ### Sneezing, bleeding, and snoring Periodic sneezing, nosebleeds, and snoring are all possible [1]. In one reported case, a cat had four months of sneezing, nasal discharge, and trouble breathing before the tumor was found [6]. ### Changes in the face and eyes Depending on which tissues the tumor affects, you may see deformities of the face or mouth, or an eyeball that appears to push outward [1]. Excessive tearing and inflammation of the cornea can also occur [1]. In a study of cats with sinonasal disease, unilateral ocular discharge was strongly associated with neoplasia, meaning cancer was much more likely in cats with one-sided eye discharge [7]. ### Breathing and neurologic signs Some cats develop noisy or stertorous breathing [6]. If the tumor extends toward the brain, cats can show disorientation, blindness, seizures, and coma [1]. These are serious signs that need urgent care. ### What makes owners call the vet The pattern that matters most is a nasal problem that keeps coming back, affects one side more than the other, or includes blood. If your cat has been treated for a nasal infection more than once without lasting improvement, ask your veterinarian whether imaging is warranted. ## Causes and Risk Factors The exact cause of most nasal tumors in cats is not well established in veterinary research. What is known is who tends to be affected. - Age: the average age at diagnosis is 12 years [1]. - Sex: the incidence is higher in male cats [1]. - Tumor biology: more than 90% of nasal tumors in cats are malignant [1]. There is no proven household exposure, food, or lifestyle factor that owners can point to as the cause. If your cat is a senior, that alone raises the index of suspicion when nasal signs drag on. ## How Sinus Tumors in Cats Are Diagnosed ### History and physical exam Diagnosis starts with the history and clinical signs [1]. Your veterinarian will ask how long the discharge has been present, whether it is one-sided or two-sided, and whether there has been any bleeding or facial swelling. ### Imaging Nasal x-rays or a CT scan may show evidence of a tumor [1]. CT is preferred because it provides better detail than x-rays when trying to tell tumors of the nose apart from other causes of chronic nasal discharge [1]. In a comparison of the two first-line procedures, CT led to a conclusion of nasal tumor in 92% of cases, compared with 64% for rhinoscopy [2]. CT also helps your vet see whether bone has been eroded. Findings linked to cancer in cats include lysis (destruction) of the ethmoturbinates, the dorsal or lateral maxilla, the vomer bone, and the ventral maxilla, plus abnormal soft tissue or fluid in the sphenoid sinus, frontal sinus, or retrobulbar space [7]. ### Biopsy A biopsy of tumor tissue provides a definite diagnosis [1]. Tissue can be collected with an endoscope, as in one case where an endoscopic-guided biopsy of a mass in the right nasal cavity and sphenoidal sinus confirmed B-cell lymphoma [6]. The biopsy result matters because lymphoma and carcinoma are treated differently. ### A simple comparison of tests | Test | What it shows | Main limitation | |---|---|---| | Nasal x-rays | Possible tumor presence | Less detail than CT [1] | | CT scan | Tumor location, bone erosion, sinus involvement | Requires anesthesia in most cats | | Rhinoscopy | Direct view and ability to biopsy | Lower detection rate than CT [2] | | Biopsy | Definite diagnosis and tumor type | Needs a sample of the mass [1] | If your cat has other senior health issues, your vet may also screen for common conditions that can complicate anesthesia. You can read about [Feline Hyperthyroidism: Signs, Diagnosis, and Treatment](/knowledge/veterinary-medicine/clinical-methods/feline-hyperthyroidism-signs-diagnosis-and-treatment) and [Cat Hypothyroidism: Symptoms, Diagnosis, and Treatment Options](/knowledge/veterinary-medicine/senior-and-chronic-care/cat-hypothyroidism-symptoms-treatment) for background on two of them. ## Treatment Options for Feline Sinonasal Tumors Treatment depends on the tumor type, how far it has spread, and your cat's overall health. There is no single best plan for every cat. ### Radiation therapy Radiation is a common option, especially for lymphoma, which is generally radiosensitive [5]. In one study comparing palliative hypofractionated radiotherapy, chemotherapy, and a combination of the two for cats with nasal lymphoma, there was no significant difference in overall survival or progression-free survival among the three groups [4]. That finding suggests similar results can be achieved with any of these approaches [4]. ### Chemotherapy Chemotherapy is used for lymphoma and sometimes for carcinoma. In a study of cats with nasal carcinoma, 33 cats were divided into an antineoplastic treatment group and a palliative treatment group, and the researchers reported response rates, time to progression, and survival for both [3]. Medical therapy data in cats are still limited, so your veterinarian will discuss what is realistic for your cat's specific tumor [3]. ### Surgery Surgery has been described for nasal tumors, often combined with radiation [3]. In one case, functional endoscopic sinus surgery completely removed a B-cell lymphoma and restored normal nasal flow, with no recurrence for 15 months afterward [6]. That is a single case, so it does not predict what will happen for every cat. ### Palliative procedures When a tumor blocks the nasal passage and other options are exhausted, a procedure called nasal hydropulsion can be used to dislodge the mass and temporarily reopen the airway. In one report, an 8-year-old cat and a dog each had the procedure repeated four times over at least a year as a last-resort palliative treatment, with temporary relief each time [8]. Minor complications included self-limiting swelling behind the eye and in the throat in the cat, and self-limiting nosebleeds in both animals [8]. This is not a cure, and it is not right for every cat. ### Comfort care Palliative care focuses on keeping your cat comfortable. This can include pain management, keeping the nose clean, humidified air, and appetite support. If your cat has other tumors or chronic conditions, your veterinarian will factor those in. For a look at how cancer care decisions are made in another common feline cancer, see [Feline Mammary Tumors: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-mammary-tumors-diagnosis-management). Any medication dose is calculated by your veterinarian based on your cat's weight and health. Never give human medications to a cat without veterinary guidance. ## Recovery, Outlook, and Long-Term Management The outlook varies widely by tumor type and treatment. Untreated, survival is generally 3 to 5 months after diagnosis [1]. With treatment, some cats do much better, and some do not respond. In the nasal carcinoma study, 48% of cats had worsening of clinical signs, 36% remained stable, and 16% showed clinical benefit [3]. Those numbers are a reminder that response to treatment is not guaranteed. For nasal lymphoma, radiation, chemotherapy, or a combination produced similar survival outcomes in one study [4]. Research on markers like apoptosis and Ki-67 suggests these may someday help predict which lymphomas respond best to radiation, but this is still an area of active study [5]. Long-term management usually means regular rechecks, monitoring for return of nasal signs, and watching for neurologic changes. If your cat has a nasal tumor plus another condition, such as a skin problem, treating both can improve day-to-day comfort. [Cat Skin Infection: Signs and Treatment Options](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-skin-infection) covers one common issue that can flare during illness. ## Prevention There is no known way to prevent sinus tumors in cats. The risk factors identified so far (older age, male sex) cannot be changed [1]. What you can do is pay attention to persistent nasal signs and get them evaluated instead of assuming they are just another infection. Early imaging gives you more options. ## Limitations and When to Contact a Veterinarian This article cannot tell you what is happening in your cat's nose. Only a veterinarian who examines your cat, reviews imaging, and possibly reads a biopsy report can do that. Individual cases need individual veterinary care. Contact your veterinarian the same day if your cat has: - Sudden heavy bleeding from the nose - Trouble breathing or open-mouth breathing - A new facial swelling or an eye that looks pushed out - A marked drop in appetite or energy Go to an emergency clinic now if your cat has a seizure, seems disoriented, goes blind suddenly, or becomes unresponsive. These can signal tumor spread toward the brain [1]. Schedule a routine visit if your cat has had one-sided nasal discharge, sneezing, or nosebleeds for more than a week or two, especially if a course of antibiotics did not fix it. ## Frequently Asked Questions ### How common is a sinus tumor in cats? It is relatively uncommon compared with dogs, but the incidence is higher in male cats [1]. Because the signs mimic ordinary nasal disease, many cases are not suspected until imaging is done. ### Can a nasal tumor in cats be cured? Sometimes a tumor can be removed or controlled for a long period, as in one cat that had no recurrence for 15 months after endoscopic surgery [6]. In many cases, the goal is control and comfort instead of a cure. Your veterinarian will tell you what is realistic for your cat's tumor type. ### Is nasal lymphoma different from nasal carcinoma? Yes. Lymphoma is the most common nasal tumor in cats and is generally radiosensitive, while carcinoma is the second most common and tends to behave differently [3][4][5]. The biopsy result is what separates them and guides treatment. ### Will my cat need anesthesia for testing? Most cats need anesthesia or heavy sedation for a CT scan, rhinoscopy, or biopsy. Your veterinarian will assess your cat's heart, kidneys, and other organs first. If your cat has a concurrent condition, that will be factored into the plan. ### What can I do at home to keep my cat comfortable? Keep the nose clean, use a humidifier, and offer soft, smelly food to encourage eating. Ask your veterinarian about pain control and any nasal drops or rinses. Never give over-the-counter human drugs, since many are toxic to cats. ## Related Articles - [Feline Feline Mammary Tumors: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-mammary-tumors-diagnosis-management) - [Feline Hyperthyroidism: Signs, Diagnosis, and Treatment](/knowledge/veterinary-medicine/clinical-methods/feline-hyperthyroidism-signs-diagnosis-and-treatment) - [Cat Skin Infection: Signs and Treatment Options](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-skin-infection) - [Ear Polyps in Cats: Signs, Diagnosis, Surgery, and Recurrence](/knowledge/veterinary-medicine/clinical-methods/ear-polyps-in-cats) - [Cat Hypothyroidism: Symptoms, Diagnosis, and Treatment Options](/knowledge/veterinary-medicine/senior-and-chronic-care/cat-hypothyroidism-symptoms-treatment) - [Nasal Tumors in Cats: Treatment Options Explained](/knowledge/veterinary-medicine/senior-and-chronic-care/nasal-tumors-cats-treatment) - [Tumors on a Cat's Mouth, Jaw, or Tongue: What to Do](/knowledge/veterinary-medicine/dental-care/cat-mouth-jaw-tumor) - [Bone Cancer in a Cat's Face or Skull: Signs and Options](/knowledge/veterinary-medicine/senior-and-chronic-care/bone-cancer-cat-face-skull) ## References 1. [Cancers and Tumors of the Lung and Airway in Cats - Cat Owners](https://www.merckvetmanual.com/cat-owners/lung-and-airway-disorders-of-cats/cancers-and-tumors-of-the-lung-and-airway-in-cats). Merck Veterinary Manual. 2. [Computed tomography or rhinoscopy as the first-line procedure for suspected nasal tumor: a pilot study](https://pubmed.ncbi.nlm.nih.gov/25694669/). The Canadian veterinary journal = La revue veterinaire canadienne, 2015. 3. [Tolerability and Outcome of Medical Treatment in Feline Nasal Carcinomas: A Multi-Institutional Retrospective Study](https://pubmed.ncbi.nlm.nih.gov/42781880/). Veterinary and comparative oncology, 2026. 4. [Efficacy of chemotherapy and palliative hypofractionated radiotherapy for cats with nasal lymphoma](https://pubmed.ncbi.nlm.nih.gov/33473067/). The Journal of veterinary medical science, 2021. 5. [Apoptosis and Ki-67 as predictive factors for response to radiation therapy in feline nasal lymphomas](https://pubmed.ncbi.nlm.nih.gov/27086717/). The Journal of veterinary medical science, 2016. 6. [Functional endoscopic sinus surgery in a cat with nasal tumor](https://pubmed.ncbi.nlm.nih.gov/31270284/). The Journal of veterinary medical science, 2019. 7. [Association between clinical characteristics, computed tomography characteristics, and histologic diagnosis for cats with sinonasal disease](https://pubmed.ncbi.nlm.nih.gov/16700173/). Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association, 2006. 8. [Hydropulsion as Palliative, Long-Term, Last-Resort Treatment of Nasal Carcinoma in a Dog and a Cat](https://pubmed.ncbi.nlm.nih.gov/31433223/). Journal of the American Animal Hospital Association, 2019. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)